We have the bunk option. It is easy to use (set up & take down) & the pieces conveniently store under the queen bed out of the way when not in use.
I cannot say that I've actually slept a whole night on it yet to determine how comfortable it is from a sleeping perspective. Our kiddos are still small enough that they both fit on the dinette bed so we haven't had to actually use it yet.
I've been meaning to set it up & try sleeping on it just to see how comfortable it is. So far I've only just set it up & laid down on it to get a quick feel & it seems reasonably comfortable. I think its particularly well suited for someone who sleeps on their back &/or side but likely less so for a stomach sleeper. It's basically a cot but more comfortable in that it doesn't have any cross bars.
Since I haven't had another trailer with a traditional egg bunk, I don't know how it compares to that from a comfort standpoint. One thing I do like is that it is rated for a lot heavier weight than the traditional egg bunk (200 lb vs 60/80 lb)
The previous thread with pics is titled "Gaucho Bunk Option"
I believe that I posted a link with pictures of ours in the "Grasshopper" thread. There should be 4-5 pics from different viewpoints of the bunk set up.
Personally, I think the step up in bed size on the 19 would be worth it for your case. The queen bed is awesome and the dinette bed is approx the size of the 17's rear bed & the bunk should suffice for your kids even as they grow (or you for that matter). IMO another benefit of stepping up to the 19 for your family is the little bit of extra width which makes it easier to pass each other when moving about the inside of the trailer.